And the LORD spake unto Moses, Say unto Aaron, Take thy rod, and stretch out thine hand upon the waters of Egypt, upon their streams, upon their rivers, and upon their ponds, and upon all their pools of water, that they may become blood; and that there may be blood throughout all the land of Egypt, both in vessels of wood, and in vessels of stone.
19. And the Lord spake unto Moses. This is the more extended narrative of which I spoke; for Moses mentions nothing different from what went before, but explains more distinctly his mode of action in the performance of the miracle, namely, that what God had commanded was completed by the instrumentality of Aaron.
Water turned to blood strikes horror into the soul, but the justice runs deeper: Egypt made an idol of the Nile, and God justly turned their god into a curse. Whatever creature we worship instead of the Creator, the Lord will either remove from us or make bitter to our taste.
AI summary
Commenting on Exodus 7:14-25
And the Lord spake unto Moses,.... Pharaoh still being obstinate, and refusing to let the people go: say unto Aaron, take thy rod, and stretch out thine hand upon the waters of Egypt; upon all of them in general, what were in the river Nile, or derived from it, as follows: upon their streams; the seven streams of the river Nile; see Gill on Isa 11:15.